On Fri, Jul 26, 2019 at 1:02 PM Peter Sabaini <pe...@sabaini.at> wrote:
> On 26.07.19 15:03, Stefan Kooman wrote: > > Quoting Peter Sabaini (pe...@sabaini.at): > >> What kind of commit/apply latency increases have you seen when adding a > >> large numbers of OSDs? I'm nervous how sensitive workloads might react > >> here, esp. with spinners. > > > > You mean when there is backfilling going on? Instead of doing "a big > > Yes exactly. I usually tune down max rebalance and max recovery active > knobs to lessen impact but still I found the additional write load can > substantially increase i/o latencies. Not all workloads like this. > We have been using: osd op queue = wpq osd op queue cut off = high It virtually eliminates the impact of backfills on our clusters. Our backfill and recovery times have increased when the cluster has lots of client I/O, but the clients haven't noticed that huge backfills have been going on. ---------------- Robert LeBlanc PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1
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